巻号一覧
43 巻 (1990)
- 4 号 p. 459-
- 3 号 p. 311-
- 2 号 p. 179-
- 1 号 p. 1-
前身誌
43 巻, 2 号
選択された号の論文の15件中1～15を表示しています
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梶川 昌三, 増田 幸治, 山田 功夫, 出原 理1990 年 43 巻 2 号 p. 179-188
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーWe studied experimentally the effects of grain size on brittle properties of two kinds of granite with quite different mean grain size. These granite samples in much the same mineral composition (mode) were prepared, and these were classified into two groups in terms of their mean grain size; one with grain sizes between 3.0 and 5.0mm and the other with grain sizes between 0.5 and 1.0mm. In order to investigate the behavior of microcracks in the sample, we measured the axial stress, axial and circumferential strains, elastic-wave velocities along the direction perpendicular to the loading axis and the number of AE events (acoustic emission activity) during loading. The results were analyzed in conjunction with the growth of stress-induced cracks during loading. We analyzed the relation between the degree of dilatancy and the cumulative number of AE events. We also analyzed the velocity change during loading in terms of the increase in penny-shaped cracks during loading with a simple assumption about the orientation of these cracks. These analyses indicate that the coarsegrained granite produces larger volumetric cracks than the fine-grained granite and that, for both the granites, the crack volume decreases when the normalized stress (stress relative to fracture stress) reaches about 0.95. Crack density of the cracks with their fiat planes parallel to the final fracture plane increases acceleratively just before the ultimate fracture. The crack density of coarse-grained granite is higher than that of fine-grained granite. The aspect ratio of stress-induced cracks was estimated to be about 1/400 and 1/150 in coarse- and fine-grained granites, respectively. These results suggest that the stress state in rocks depends on scale of inhomogeneity in them.抄録全体を表示PDF形式でダウンロード (2606K) -
震度と驚き・恐さおよび行動との関係寺島 敦1990 年 43 巻 2 号 p. 189-198
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーIt gives us one of the fundamental informations for the counterplan of earthquake disaster prevention to survey how inhabitants faced with strong earthquake motions behave differently, in the regions of high and low seismicities. This study is done by questionnaire about the matter mentioned above. The survey region with low seismicity is the area effected by strong motions of the earthquake (May 30, 1984, M: 5.6) which occurred in the southwestern part of Hyogo Prefecture. The surveys in the cases of Ohita earthquake (April 21, 1975, M: 6.4) and Off Miyagi Earthquake (June 12, 1978, M: 7.4) were already done by OMOTE and MITSuNAMI (1976) and OMOTE et al. (1980), for the regions of high seismicities, respectively. The findings of their papers are referred to the present paper to compare their findings with the results of the current questionnaire. The results are as follows: Responding to JMA intensity scale 5, one hundred percents of the inhabitants in the region of low seismicity act involuntarily and instinctively, while onle 10% of those in the region of high seismicity do so. The findings suggest that the inhabitants in the region of low seismicity are apt to cause secondary disasters such as panic, fire and the like, at lower seismic intensity than those in the region of high seismicity.抄録全体を表示PDF形式でダウンロード (1051K) -
松本 則夫1990 年 43 巻 2 号 p. 199-204
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーA simple and useful method is proposed for the interpolation of missing data in time series of groundwater level and barometric pressure observed for earthquake prediction. The basic idea of the method is that the interpolation problem is translated to the estimation of trend component of the missing time series. The trend is assumed to satisfy a second order stochastically perturbed difference equation. The equation is expressed in a state-space representation, and the likelihood of unknown variances is computed by Kalman filter algorism. The values of variances which maximize the likelihood are selected. To see the performance of the method, barometric pressure records, which is 10% and 15% missed respectively, are analyzed by the method. The method is compared with conventional linear interpolation method using same data sets. The proposed method can reproduce the original data better than the linear interpolation method in both time and frequency domain and can interpolate up to 15% missing data with sufficient accuracy.抄録全体を表示PDF形式でダウンロード (667K) -
吉田 明夫1990 年 43 巻 2 号 p. 205-212
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーCharacteristics of seismic activity in the western part of Kanagawa prefecture, central Japan, where a large earthquake is expected to occur in the near future, are investigated. There is a conspicuous seismic zone along the western border of Kanagawa prefecture in the direction connecting the Yamanashiken-tobu active region to Odawara city. We tentatively call the seismic zone Doshi-Odawara seismic zone in this paper. Temporal correlation is observed between seismic activity in the northern part and that in the southern part of the seismic zone. The Yamanashiken-tobu seismic region is divided into two parts at the northern extension of the zone; the western part is more active than the eastern part. “The Nishi-Sagamiwan Danretsu”, which was proposed by ISHIBASHI (1988a, b) to represent a split of the Philippine Sea plate, is parallel to the Doshi-Odawara seismic zone. However, the southern half of “the Nishi-Sagamiwan Danretsu”, from the headland of Manazuru to the Ito-oki swarm region, is not seismically active. The western boundary of the Doshi-Odawara seismic zone is sharply cut, and the plane which separates the seismic zone from western aseismic region seems almost vertical. It is proposed that the subducting Kanto slab moves left laterally relative to the colliding Izu block at the western boundary of the Doshi-Odawara seismic zone, and the southern extension of the block boundary is continued to the Tan-na fault partially through the Hakone volcanic area. Large activity of the Tan-na fault can be understood by considering that it represents partly the relative motion between the Kanto slab and the Izu block. A notable doughnut pattern is observed to the east of the Doshi-Odawara seismic zone. Within that gap the Oiso hills, the Ashigara plain and the Hadano basin are located. It is to be noted that the seismicity around Odawara city which corresponds to the southern end of the Doshi-Odawara seismic zone has remarkably decreased since the beginning of 1988.抄録全体を表示PDF形式でダウンロード (1077K) -
花籠 靖, 中西 一郎, 森谷 武男, 笠原 稔1990 年 43 巻 2 号 p. 213-225
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーThe rapid determination of seismic moment and source mechanism for near earthquakes is attempted by a moment tensor inversion of long-period seismic waves. The inversion method is based on a normal mode theory. The data for the inversion are recorded at three stations in Hokkaido, Japan. Each station is equipped with a three-components very-broad-band seismograph. Source parameters of six earthquakes (mb_??_5.5) in and around the Japan region (epicentral distances of 200 to 1500km) for the period from January to April 1989 are determind by applying the moment tensor inversion to the long-period waveform data. Changing the components (UD, NS, EW) and record length used in the inversion the stability in the moment tensor solution is examined. A good S/N ratio is required to obtain a stable solution in the inversion of three-components data from a single station. Data length of 4-8min after the earthquake origin time is enough to attain stable source mechanism determination by using the three-stations data.抄録全体を表示PDF形式でダウンロード (1319K) -
羽鳥 徳太郎1990 年 43 巻 2 号 p. 227-232
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーIt is reported by an old document that the Yamagata-Oki earthquake of Dec. 7, 1833 (Oct. 26, Tenpo 4), hitting the Yamagata, Niigata and Akita districts destroyed 475 houses in the Shonai plain and the tsunami killed about 150 persons. In this paper the distributions of the seismic intensity and the tsunami behavior along the Japan Sea coast are investigated with an addition of newly collected data. The magnitudes of earthquake and tsunami are compared with those of the 1964 Niigata and the 1983 Japan Sea earthquakes. The results are summarized as follows:
1) According to the intensity-distance diagram, the earthquake, magnitude is inferred as M=7.5, because the same intensity area is smaller than that of the 1983 Japan Sea earthquake and similar to that of the 1964 Niigata earthquake.
2) By judging from the tsunami height-distance diagram (HATORI, 1986), tsunami magnitude on the Imamura-Iida scale is m=2.5, which are somewhat larger than the former value. Extraordinary run-up heights at Wajima (tip of Noto peninsula) and Oki Islands located in far field may be caused by the refractive effect and the reflected waves from the continental coasts.抄録全体を表示PDF形式でダウンロード (640K) -
地殻熱流量計測を例に古田 俊夫, 藤本 博巳, 中西 正男, 村上 英幸1990 年 43 巻 2 号 p. 233-241
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーAcoustic digital data telemetry makes it possible to retrieve the observed values on a surface ship at any time during long-term underwater measurement. Several sea trials have been carried out totest feasibility and reliability of the telemetry by means of acoustic pulses from an ocean bottom heat flow meter newly developed for long-term measurement. More than 90% of values retrieved by the acoustic telemetry is in good agreement with ones memorized in the bottom equipment and recovered later. Bit length of each acoustic pulse for this data telemetry can be selected from 100msec to 10msec in accordance with the ambient acoustic noiselevel. Under normal sea states, 20msec is sufficient length of a pulse for the data retrieval from a depth of 6, 000 meters.抄録全体を表示PDF形式でダウンロード (2611K) -
伊豆半島東方沖付近の地震・火山活動との関連吉川 清志, 永井 茂1990 年 43 巻 2 号 p. 243-256
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーWe have investigated discharge rate and water temperature at the hot spring wells in the eastern Izu Peninsula to consider whether or not they are sensitive to crustal stress changes. In this paper the result at Akazawa hot spring well No. 6 (594m-deep-well) is described. A 9m long strainer is installed at the deepest part of the well, where the water comes only from a single crack. Fluctuations of the water temperature can be explained by following two reasons. One is change in cooling effect due to the fluctuations of discharge rate, and the other is change in heating effect due to the fluctuations of flow rate of the water passing through heat source. We could not find any change in water temperature caused by volcanic eruption. On the other hand, it is suggested that the effect of earthquakes on discharge rate of the well is more sensitive than the effects of oceanic and earth tides, precipitation and barometric pressure. Changes in the discharge rate by the earthquakes which occurred in the east off Izu Peninsula and near Izu Oshima correlate with crustal stress changes. As the result of the investigation, we evaluated the Akazawa hot spring well No. 6 is a good observation well for crustal stress changes.抄録全体を表示PDF形式でダウンロード (1905K) -
武村 雅之1990 年 43 巻 2 号 p. 257-265
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーThe relation between seismic moment M0 and magnitude M of JMA (Japan Meteorological Agency) is examined for the earthquakes of M>5 in and around Japan. The data for the events in subduction zones including the earthquakes along eastern margin of the Japan sea are approximately explained by the relation as
logM0=1.5M+16.2(1)
This equation was proposed by SATO (1989) based on the similarity relation of source parameters. In consideration of the difference between M and surface-wave magnitude Ms, the equation (1) can be modified so as to describe more detailed trend of the data distribution of M0 and M. On the other hand, the data for inland events which occurred in the upper crust cannot be explained by the equation (1). Another relation is available for these events as follows:
logM0=1.17M+17.72(2)
Two reasons are possible for the difference of the M0-M relations between the events in the subduction zone and in the inland. One is that the stress drop of the inland events is larger than that of the subduction events. The other is that the inland events show large excitation of surface-waves in the medium periods, because the focal depths of them are shallower on the average, comparing with those of the events in the subduction zone. The JMA magnitude is determined from the maximum amplitudes of seismic waves in the medium period range, which are usually given not by S-waves but by surface-waves for large events. This fact supports the latter reason.抄録全体を表示PDF形式でダウンロード (1094K) -
その2 世帯に及ぼす影響の時間変動性 -算定例-太田 裕, 岡田 成幸1990 年 43 巻 2 号 p. 267-278
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーA series of studies has been conducted for further development of urban seismic risk assessments, laying emphases on the causal and time dependent damage and restoration characteristics. In the previous paper a methodology was developed in which major seismic effects on a household can be traced as a set of functions of the time elapsed after an earthquake and can be integrated into one synthetic index of “household's living standards”. This paper reports case studies to evaluate seismic effects on a household in a hypothetical city in Japan. The obtained results are as follows:
1. Test runs proved the developed methodology to be effective for describing temporal changes of seismic effects, individually and synthetically, on a household in damage and restoration processes.
2. The household's living standards have a general trend that shows a sharp drop immediately after an earthquake, lowering farther if earthquake fires are significant, and recovers slowly to the original level.
3. The deterioration in the living standards depends not only on the severity of seismic input but also on various social conditions of an area such as population density. In major Japanese cities, the spread of earthquake-triggered fires is inevitable at a JMA intensity of higher than mid-VI, because of high concentration of wooden houses, so that the living standards drop markedly.
4. It takes 5 or more years to regain the original living standards before a large earthquake occurrence. This suggests that the existing earthquake countermeasures should be improved in much more attention of long-term socio-economic effects.抄録全体を表示PDF形式でダウンロード (1173K) -
西村 太志1990 年 43 巻 2 号 p. 279-282
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (439K) -
青木 治三1990 年 43 巻 2 号 p. 283-285
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (355K) -
藤縄 幸雄, 高橋 耕三, 熊谷 貞治1990 年 43 巻 2 号 p. 287-290
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (549K) -
平原 和朗1990 年 43 巻 2 号 p. 291-306
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーSeismic tomography has revelaed the three-dimensional structure of Earth's interior in several scales, which has improved our understanding of geophysical and geological processes in the Earth. The present paper reviews three-dimensional inversion methods of seismic body-wave data, stressing the technical details encountered in actual analyses of travel time data. Especially, the paper gives the detailed description of the formulation of three-dimensional inversion problems, the parameterization of structure, the technique of parameter separation, and solving methods of observational equations with resolution analyses (a matrix and interative back-projection methods).抄録全体を表示PDF形式でダウンロード (2418K) -
浜田 信生1990 年 43 巻 2 号 p. 307-310
発行日: 1990/06/24
公開日: 2010/03/11
ジャーナル フリーPDF形式でダウンロード (473K)
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